libX11 XkbGetMap Reply Heap-based Buffer Overflow (CVE-2026-88806) | HOL Guard CVE

Unknown severity · Source severity not reportedCVE-2026-88806

libX11 XkbGetMap Reply Heap-based Buffer Overflow

Answer in brief

CVE-2026-88806 records a Unknown severity vulnerability in libX11 XkbGetMap Reply Heap-based Buffer Overflow. The current sources do not mark it as known exploited. The current feed maps x.org/libX11 (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Sep 21, 2026Updated Sep 21, 2026Source checked Sep 21, 2026First seen by HOL Sep 21, 2026Material review Sep 21, 2026

Upstream Advisory

Key facts

Risk: Unknown severitySource severity not reported
Exploitation: Not marked as known exploited
Affected software: 1 mapped package or product
Fix availability: Available

Why this deserves its current priority

A CVSS score is not reported in the current record. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps x.org/libX11 (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
x.org/libX11generic	>=0 <1.8.14	1.8.14

Recommended response

Check inventory. Check lockfiles and deployed manifests for x.org/libX11.
Review the reported fix. Update x.org/libX11 to 1.8.14 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Sep 21, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Sep 21, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Sep 21, 2026

Sources and claim methodology

Source referencegitlab.freedesktop.org

Upstream source description

A malicious X server could exploit a buffer overflow in libX11 before 1.8.14 during handling of XkbGetMap overflowing the key_sym_map.

Quoted source text, attributed separately from HOL analysis.